Guide 2nd Generation CX-9: Aftermarket oil catch can installation

sm1ke

2018 Mazda CX-9 Signature
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Canada
This is a DIY How-To for an aftermarket oil catch can installation on the 2nd Generation Mazda CX-9. I decided to document this process because, while a few others have successfully installed their own catch cans and provided some detail, I wanted to improve on their experience and also include some photos of the install.

This process was documented/photographed by myself, using my crappy cellphone camera and my 2018 Mazda CX-9 Signature as the "demo" vehicle. This DIY is provided as a learning aid and reference guide. I assume no responsibility for any warranties this process may void, or damages you may inflict on yourself or your vehicle.

First and foremost, I want to credit users RATTL3R and Silly Wabbit for taking the first steps in documenting the oil catch can installation. Without their insight, I might still be trying to figure out where the PCV valve is, haha.

Here is RATTL3R's post: LINK
And here's the thread that Silly Wabbit posted in: LINK

Here's some background info:
Wiki description: What is an Oil Catch Can?
A PDF explaining where the OCC should be mounted (Page 13): View attachment p-2273-arrington_ccv_bible.pdf
CorkSport's OCC article: Why do you need an OCC?

The CX-9 comes factory equipped with an oil separator that does a good job of keeping blow-by to a minimum. That said, the system can still be improved upon, which is part of the reason I chose to install an oil catch can on my own CX-9.

I've had an unbranded oil catch can in my possession for a couple of months now, and was dragging my feet with the install. At first, this was due to bad weather, but most recently I've been preoccupied with moving to a different province. After seeing CorkSport's recent article about oil catch cans, I decided to get off my ass and install the one I had.

You can use these instructions with virtually any oil catch can available for the CX-9, and there are plenty to choose from. CorkSport makes one for $240 (and also offers a drain plug kit for their OCC for an additional $33). There are also branded (Cusco, Mishimoto, etc.) and unbranded universal oil catch cans all over amazon, eBay, and various online resellers - all with varying levels of fit, finish, size/capacity, and bling factor. I chose to go with a cheap, unbranded catch can that I found on eBay for $40.


*** NOTE: 08/14/2020 - The PCV hose identified in this guide is the same hose that CorkSport identifies as the PCV hose in their installation instructions (see here), but they use a different method of installation that involves capping the intake manifold port and tapping the valve cover hose near the turbo intake pipe. Since CorkSport's installation involves the removal of two "permanent" clamps from the valve cover hose, I chose to install it in a different way. Removal of those "permanent" clamps on the valve cover hose could result in some headaches (or a flat out denial of warranty) if I ever had any engine issues that would normally have been covered under warranty.


The cons of going with the unbranded can:
- Took a while to get to me (about a month)
- Fluid indicator is just a dipstick
- No drain plug feature
- Finish inside the can was poor
- Came with crappy tubing that is not suitable for OCC use

The pros:
- Price
- Same basic function as an expensive can
- Bottom of the can screws on/off (don't need to unhook any lines to drain)
- Small and inconspicuous
- Came with mounting hardware and fittings


What you'll need:

- Aftermarket oil catch can (mounting kit is optional)
- One 1/2" brass PEX barb coupling (male/male)
- Pliers (preferably narrow, like needle-nose pliers)
- Utility knife

The following materials will vary depending on where you choose to mount the can, what came with your can, and personal preference. I estimated that my installation would require three feet of tubing, but I got four feet just in case.

- At least four feet of 15/32" crankcase vent tubing (or 1/2" rubber fuel line. You can also use braided SS line, but fuel line is cheaper and works well enough)
- Steel wool (optional - I just cut a portion from a steel wool dish scrubber)
- Flathead or Phillips screwdriver (if using worm-gear clamps)
- Rotary tool or drill to mount the catch can
- Old rag


*Pliers and rotary tool not shown
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Now then, let's get on with the installation.
 
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1. First, decide where you want to mount your oil catch can, and make sure you have everything you need for the installation. Most kits should come with the fittings and o-rings required. Ensure that the o-rings are installed onto the fittings as shown below.

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2. My catch can did not come with a micron filter on the "OUT" side, but I don't think its that important (it's also one extra part to clean/replace). However, on the "IN" side of the catch can, there is a small, removable enclosure. This is meant to give the blow-by something to condense on before settling at the bottom of the tank. I chose to add a very small amount of steel wool to this enclosure to give the blow-by more surface area to attach to. As you can see, there is still plenty of space for airflow.

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Note: For the steel wool, I just cut a portion from a steel wool dish scrubber. This is not as fine as the steel wool you'd typically find in home improvement stores, and it's also rust resistant.


3. I chose to mount my can on the fuse cover, so I used a rotary tool to drill a couple of mounting holes. Here's a photo of the can mounted on the cover:

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4. Cut your tubing to your desired lengths (remember, measure twice, cut once). Install the tubing, then screw the fittings on to the can. As a note, the crankcase tubing was just a little too small for the fittings on this can, so I really had to muscle it on. 1/2" tubing probably would have been a bit easier to use.

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5. With the OCC mounted, we can now plumb the lines. Refer to the photo below to see where the OEM PCV hose is located (on the right side of the intake manifold, underneath the engine cover). The next photo shows how the flow will run after the installation.

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6. Remove the engine cover to get a better look at everything (just pull straight up, the cover will come right off). Using your pliers, squeeze the clamp to loosen it and move it towards the bend of the hose.

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7. Use a screwdriver with a rag over the tip to slide the hose off of the intake manifold port. It might be stuck on there pretty good, just take your time with it and it'll come off.

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8. Rotate the PCV hose so that it's facing the OCC. You might have to use your pliers to loosen the other squeeze clamp on the PCV side before you can turn the hose, but I was able to just twist the hose in the right direction. Install the 1/2" coupler and slide the squeeze clamp over the coupler to hold it in place.

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9. Slide a worm-gear clamp on to the other end of the hose from the "IN" side of the OCC, then install the hose on to the coupler. Slide the clamp on to the coupler and tighten it down.

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10. Slide a worm-gear clamp on to the other end of the hose from the "OUT" side of the OCC, then install the hose on to the intake manifold port. Slide the clamp over the port and tighten it down. The engine bay should now look like this:

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11. Start the car and make sure everything looks and sounds good. I took my car around the block a couple of times and also opened it up a bit on an empty road to test for any leaks. If everything looks and sounds good, put the engine cover back on, because that's it!



Since this install was done last night, I've only driven it around the block to test and then to work this morning (~25 KMs). So far, no issues. At the time of install, I had 11,750 KMs on the odometer. I plan to check in every 1,000 KMs to establish a baseline for how often I need to empty the OCC. All in all, I'm very happy with the way the install went and what the end result looks like. It almost looks like an OEM part :)
 
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Nice job, and great write up. Keep us informed about how much oil ends up in the OCC. I've been wavering about whether or not to do this mod, and I'd love some real world data.
 
Nice job, and great write up. Keep us informed about how much oil ends up in the OCC. I've been wavering about whether or not to do this mod, and I'd love some real world data.

Thank you. It's a fairly easy mod to do, especially if you just ziptie the can to the coolant tube instead of mounting it on the fuse cover.

SW posted in one of the threads mentioned in the OP. After 2,000 miles, he had just under 20ml of blow-by in the catch can. Besides him, I don't think anyone else has posted how much they are draining from their cans. I'll be sure to keep the thread updated for at least a few months.
 
Very nice write up and pictures detailing the process! I like your mounting location but I personally didn't want to stretch it too far. And yes, so far I've been consistently draining a touch under 20ml every 4000 miles. I am interested to see if you will drain out the same amount. If you can, please report back at 4000 miles for a comparison. :) Any other mods in the work?
 
Very nice write up and pictures detailing the process! I like your mounting location but I personally didn't want to stretch it too far. And yes, so far I've been consistently draining a touch under 20ml every 4000 miles. I am interested to see if you will drain out the same amount. If you can, please report back at 4000 miles for a comparison. :) Any other mods in the work?

No problem SW, will do. Nothing else planned at the moment, though I have played with the idea of DIY hood struts (suggested by Bingoy) and maybe a DIY air intake.. these ideas will likely just remain ideas until I piece everything together.
 
So, at the time of install I had 11,750 kms on the odometer. Yesterday, mileage was just shy of 13,000 kms, so we'll say 1250 kms (776 miles) since the install.

It may have been too early to check with only 776 miles, but when I checked the OCC yesterday it was completely empty. It looks like I had only installed it two days ago, that's how empty/dry it was. Not sure if that's normal, but it looks like at the very least, the OEM oil separator is working quite well. No issues to report since the install of the OCC, save for the OCC "sagging" a bit due to where I mounted it (on the plastic fuse cover). I do have a fix for that, but I'll hold off on posting about it until I get it done.

I have heard of people venting the crankcase pressure into the atmosphere by simply disconnecting and removing the PCV tubing, then sticking a tiny air filter on the PCV valve and a plug in the intake manifold port. While this can work, it is not advisable since the vented fumes are harmful to the environment and will cause you to fail an inspection. On top of that, the fumes can seep into the cabin, and nobody likes a car that gives you a headache every time you ride in it.
 
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Appreciate your update. I'm surprised you're not getting anything in your can. I actually just drained mine after 4k miles and got a consistent amount. Please do update us again after you put more miles. ��
 
Appreciate your update. I'm surprised you're not getting anything in your can. I actually just drained mine after 4k miles and got a consistent amount. Please do update us again after you put more miles. **

Will do. Have you been fueling with 87 or 91+? I've been fueling up with 91+ ever since I took delivery, so I decided to switch to 87 this week. We'll see if that has any effect on anything besides my wallet, lol.
 
Will do. Have you been fueling with 87 or 91+? I've been fueling up with 91+ ever since I took delivery, so I decided to switch to 87 this week. We'll see if that has any effect on anything besides my wallet, lol.
I've only used 91 in the first couple thousand miles to test out the performance and gas mileage but found no difference so I switched to 87 ever since.
 
So I switched back to 87 for 4 or 5 tanks and put over 2000 km on the car, still nothing in the catch can. I've now put nearly 5000 km on the car since install, and the can is still dry to the touch. Double-checked everything the last time I had the hood open, and as far as I can tell there are no leaks. Cabin doesn't stink when I drive so I'm assuming that the catch can isn't somehow venting into the cabin. (shrug)

I guess I'll just continue to watch it. Glad I didn't spend a lot on this mod! Haha
 
I'm surprised to the point of disbelief that after so many km the can is still bone dry. It should collect vapor from the crankcase. Mine has been consistent.
 
I'm surprised to the point of disbelief that after so many km the can is still bone dry. It should collect vapor from the crankcase. Mine has been consistent.

Yeah I don't get it either. I've had two other cars that I installed catch cans on, and they always collected something, even if just a little.

I wonder if the dip stick opening isn't tightened enough? I've hand-tightened it every time, but maybe I should look into a small o-ring, or even just sealing it altogether with some silicone.
 
2nd Generation CX 9 Aftermarket oil catch can installation

Page 5-11 of the rebuild manual covers this - no idea re colour coding, Im afraid - check with dealer?

removed smiley due to embedded link - Chris
 
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So I just checked the oil catch can again. I've put on over 6000 km since the install. There's still no blowby in the can, but there is an oily film on the inside. This leads me to believe that the location of the can is why it doesn't look like it's catching anything.

Can anyone else who has installed their can in a similar location please tell me if you've been collecting blowby in the can and approximate mileage since installation? Thanks.
 
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